﻿#define _CRT_SECURE_NO_WARNINGS 1

class Solution
{
public:
	int lengthOfLongestSubstring(string s)
	{
		int hash[128] = { 0 }; // 使⽤数组来模拟哈希表
		int left = 0, right = 0, n = s.size();
		int ret = 0;
		while (right < n)
		{
			hash[s[right]]++; // 进⼊窗⼝
			while (hash[s[right]] > 1) // 判断
				hash[s[left++]]--; // 出窗⼝
			ret = max(ret, right - left + 1); // 更新结果
			right++; // 让下⼀个元素进⼊窗⼝
		}
		return ret;
	}
};